Parametric Analysis for Monitoring 2D Kinetics of Receptor-Ligand binding

Thermal fluctuation approach is widely used to monitor association kinetics of surface-bound receptor-ligand interactions. Various protocols such as sliding standard deviation (SD) analysis (SSA) and Page's test analysis (PTA) have been used to estimate two-dimensional (2D) kinetic rates from the time course of displacement of molecular carrier. In the current work, we compared the estimations from both SSA and modified PTA using measured data from an optical trap assay and simulated data from a random number generator. Our results indicated that both SSA and PTA were reliable in estimating 2D kinetic rates. Parametric analysis also demonstrated that such the estimations were sensitive to parameters such as sampling rate, sliding window size, and threshold. These results furthered the understandings in quantifying the biophysics of receptor-ligand interactions.

中国砂鼠利什曼原虫（Leishmania gerbilli）的细微结构及动质体碱性昼白的细胞化学特性的初步研究

本文以中国砂鼠利会曼原虫（Leishmanina grbilli）为材料，对动质体的细微结构及动质体碱性蛋白的细胞化学特性作了研究。已知真细菌类染色质体中有碱性的HU蛋白与DNA结合着，动质体中是否也有碱性蛋白与DNA相结合，一直是有争议的问题。de Souza等（1978-83）证明锥虫的动质体中确有碱性蛋白存在，但迄今止，国际上还没有关于利会曼原虫动质体碱性蛋白的报导。用热三氯醋酸-偶氮洋红G法、热三氯醋酸-固绿法、碱性比布列希猩法、碳酸氨银反应（AS反应）、经亚硝酸处理后作AS反应和经碱性蛋白不同成份抽提后作AS反应等光学显微细胞化学方法以及酒精钨酸染色（E-PTA）、用乙醇-醋酸固定、DNA酶处理后作E-PTA染色和碳酸氨银反应等电镜水平的细胞化学方法进行了研究。得到了如下的结果：（1）L.gerbilli的动质体中确实含有大量的酸溶性碱性蛋白。（2）对用E—PTA染色后，动质体只有周边着色的现象作了探讨，认为是假期象。动质体中碱性蛋白与DNA的分布是一致的。（3）动质体碱性蛋白对热三氯醋酸（TCA）处理的耐受性比HU蛋白的强比组慢白的弱；动质体碱性蛋白对亚硝酸处理的耐受性和与AS液的亲和力也比组蛋白弱。（4）可以抽提富含精氨酸的组蛋白的80%Alc-0.18NHCl，和可以抽抻富含赖氨酸的组蛋白的10%Alc-0.18NHCl，都不能把动质体碱性昼白全部抽提掉。（5）与真细菌类的HU蛋白相比较。L.gerbilli的动质体的碱性蛋白看来含有较多的精氨酸成份。作超薄切片，用电镜观察了L.gerbilli的质膜及质膜下微管、鞭毛、细胞核、动质体、线粒体、复片层结构等，发现：①与其它利会曼原虫和锥虫的鞭毛基部的结构不同，L.gerbilli的鞭毛基部没有基板存在。②L.gerbilli的复片层结构特别发达，是由膜组成的同心圆或同心椭圆结构。③L.gerbilli的动质体在通常情况下作“棒”状，但我们发现它实际上是一个环状结构。这在细胞膨胀时表现得非常突出。

Injection, Transport, Absorption and Phosphorescence Properties of a Series of Blue-Emitting Ir(III) Emitters in OLEDs: a DFT and Time-Dependent DFT Study

Quantum-chemistry methods were explored to investigate the electronic structures, injection and transport properties, absorption and phosphorescence mechanism of a series of blue-emitting Ir(III) complexes {[(F-2-ppy)(2)Ir(pta -X/pyN4)], where F-2-ppy = (2,4-difluoro)phenylpyridine; pta = pyridine-1,2,4-triazole; X = phenyl(1); p-tolyl (2); 2,6-difluororophenyl (3); -CF3 (4), and pyN4 = pyridine-1,2,4-tetrazolate (5)}, which are used as emitters in organic light-emitting diodes (OLEDs). The mobility of hole and electron were studied computationally based on the Marcus theory. Calculations of Ionization potentials (IPs) and electron affinities (EAs) were used to evaluate the injection abilities of holes and electrons into these complexes.

Highly conductive, methanol resistant fuel cell membranes fabricated by layer-by-layer self-assembly of inorganic heteropolyacid

Layer-by-layer (LBL) self-assembly is a simple and elegant method of constructing organic-inorganic composite thin films from environmentally benign aqueous solutions. In this paper, we utilize this method to develop proton-exchange membranes for fuel cells. The multilayer film is constructed onto the surface of sulfonated poly(arylene ether ketone) (SPAEK-COOH) membrane by LBL self-assembly of polycation chitosan (CTS) and negatively charged inorganic particle phosphotungstic acid (VIA). The highly conductive inorganic nanoparticles ensure SPAEK-COOH-(CTS/PTA)(n) membranes to maintain high proton conductivity values up to 0.086 S cm(-1) at 25 degrees C and 0.24S cm(-1) at 80 degrees C, which are superior than previous LBL assembled electrolyte systems.

Synthesis of highly faceted multiply twinned gold nanocrystals stabilized by polyoxometalates

A novel and facile chemical synthesis of highly faceted multiply twinned gold nanocrystals is reported. The gold nanocrystals are hexagonal in transmission electron microscopy and icosahedral in scanning electron microscopy. Phosphotungstic acid (PTA), which was previously reduced, serves as a reductant and stabilizer for the synthesis of gold nanocrystals. The PTA-gold nanocomposites are quite stable in aqueous solutions, and electrochemically active towards the hydrogen evolution reaction.

Study on charge transfer reactions at multilayers of polyoxometalates clusters and poly(allylamine hydrochloride) (Grotthuss-018)

Multilayers of anionic phosphotungstic acid (PTA) clusters and positively charged protonated poly(allylamine hydrochloride) (PAH) were assembled by layer-by-layer self-assembled method on Au electrode modified by 3-mercaptopropionic acid (3-MPA). The effect of the charge of the surface of the multilayer assembly on the kinetics of the charge transfer reaction was studied by using the redox probes [Fe(CN)(6)](3-)/(4-) [Ru(NH3)(6)](2+/3+). The cyclic voltammetry experiments showed that the peak currents and peak-to-peak potential differences changed after assembling different layers on the electrode surface indicating that the charge of the surface has a significant effect on the kinetics of the studied charge transfer reactions. These reactions were studied in more detail by electrochemical impedance spectroscopy. When [Fe(CN)(6)](3-/-) was used as the redox label, multilayers that terminated with negatively charged PTA showed a high charge transfer resistance but multilayers that terminated with positively charged PAH showed lower charge transfer resistance. With [Ru(NH3)(6)](2+/3+) as the redox label, the charge transfer resistance at multilayers that terminated with positively charged PAH was much higher than at the multilayer terminated by the negatively charged PTA.